Outlook
Five-year survival rates for NHL range from 20 - 95% depending on the lymphoma type, stage, age of the patient, and other variables. Because the outlook varies so widely, making a definite prognosis is very difficult, however. For example, patients with very slow growing (indolent) lymphomas can live many years. However, they are usually diagnosed at a late stage, when the cancer has spread, which reduces the survival rate. Aggressive lymphomasare more likely to cause rapid death, but they are also often curable. New drugs that target specific factors in the tumor cells are improving survival rates.
Outlook for Indolent (Low-Grade) Lymphomas
Follicular lymphomas, the most common indolent (slow-growing) NHLs, are potentially curable in early stages I and II. Unfortunately, however, these slow-growing malignancies produce no symptoms until they are in advanced stages. In most cases, these lymphomas are not diagnosed until they have spread to other sites, including the spleen and bone marrow. In such cases, they are hard to cure. Predicting outcome for indolent follicular lymphomas is more difficult than for aggressive lymphomas. Even if treatment achieves a response, these tumors almost always recur. Even after relapse, however, the tumors are retreatable if they are still very slow-growing.
In general, the average survival rate for follicular lymphoma is 7 to 10 years, depending on other risk factors. New drug treatments, particularly monoclonal antibodies, have significantly improved survival rates. According to a 2005 study, 91% of patients with follicular lymphoma now survive the first 4 years after diagnosis, compared with 69% of patients treated in the past with older types of drugs. The research team found the best 4-year survival rates for patients treated with the CHOP (cyclophosphamide, doxorubicin, vincristine, prednisone) chemotherapy regimen followed by MAbs (rituximab or iodine-131 tositumomab).
Factors for Predicting Outlook in Indolent Lymphomas. Six risk factors are proving to be useful for predicting outlook:
- Being male
- Being older
- Having stage III or IV disease
- Elevated levels of the enzyme lactate dehydrogenase (LDH)
- The presence of B symptoms
- Erythrocyte sedimentation rate over 30
Patients with a good chance for a positive outcome (65% chance for survival rates of 10 years or greater) have one or none of these factors; those with intermediate risk (23%) have two factors, and those likely to have a poor outcome (11%) have three or more factors. MALT lymphomas generally have a good prognosis. Primary gastric lymphomas have a 3-year survival rate of 89%.